Help with over pressure but no change to load

[rideold]

I'm trying to understand over pressure signs for a load that I didn't change. I'm loading 120 gr Barnes TTSX bullets for 6.5 CM over 43.5 gr of Accurate 2700. The rifle is a Savage 110 Hunter. I worked up to the load last year for my son to deer hunt with and all seemed just fine. Regular bolt feel, primers looked fine. He hunted with this load last fall with success. I've been taking him to the range every other week for the last couple of months and he's gone through 100+ rounds. The last reloading was the third on this group of cases and we had some primers fall out after firing. They went back in by hand and the cases were Winchester chromed brass. After reading that these can be of lower quality I removed them from the pool. Just to be sure we didn't have a carbon ring increasing pressure we did a thorough cleaning of his rifle. I loaded up some twice fired Nosler brass and we went to shoot last weekend and had a stiff bolt and flattened primers. We didn't change a thing from last year or this fall. The same batch of powder and primers were used. The ambient temperature was in the upper 60s or lower 70s. Any advice? Start over with a ladder? Have the rifle looked at? I've purchased some factory Barnes for his hunt next week to be on the safe side.

 

[JT88]

Was the load developed in colder temps? If not, maybe you could be seeing the difference in case capacity between different brands of brass. How many rounds have been fired thru the rifle?

Sounds like the load may be on the "too hot" side regardless if you're popping primers

 

[std7mag]

You switched from Winchester casings to Nosler.
More than likely the Noslers are thicker, meaning there is less room inside, hence raising pressures.

You were running near/at the high end of your charge to begin with if you were getting loose primer pockets after the 3rd reload.

Cases ARE a component!!
New workup for different components.

 

[Dan O]

Did you change lots of powder? There can be a difference in the same powder but different lots.

 

[Sheltowee]

^what all of these guys are saying, plus-- have you trimmed the cases? If your case necks are getting too long, they may also causes pressure increases.

 

[Benfromalbuquerque]

I’ve used AA2700 in my 270 Win, also 110 Hunter, with good success at lower weight bullets. I think it’s fair to say most all Accurate/Ramshot powders run high pressure and it may be best to drop to a lower weight Barnes. Alternatively, 6.5 Staball freakin rules! That powder has bugholed every weight bullet I’ve put it behind.

 

[Sheltowee]

I’ve used AA2700 in my 270 Win, also 110 Hunter, with good success at lower weight bullets. I think it’s fair to say most all Accurate/Ramshot powders run high pressure and it may be best to drop to a lower weight Barnes. Alternatively, 6.5 Staball freakin rules! That powder has bugholed every weight bullet I’ve put it behind.

Teach me your ways. I couldn't get Staball to pattern Barnes LRXs from my Tikka 6.5 Creed for the life of me, even after playing with seating depth.

 

[Benfromalbuquerque]

Teach me your ways. I couldn't get Staball to pattern Barnes LRXs from my Tikka 6.5 Creed for the life of me, even after playing with seating depth.

Consistency got me there. I log all of my loads, case preparations. It’s easier to make changes then because everything else is static; only one variable changed or added to the load.
If you already do all of that too then try adding light crimp. It worked for me! You could either remove seating stem once seated and screw down the die 1/2 turn or leave all that alone, add Lee Factory Crimp die at the end of your process.
6.5 Staball is close to yet slower than H100V (think both are St. Mark’s creations). It’s very temp tolerant and low pressure. Barnes puts max load at 44g, Hodgdon max is 44.8g with both advising 2.75” OAL.
How about load up 43g, 44g, 45g keeping all else within recommended trim, seating, yadda yadda and add the same light crimp to all these test loads?

 

[WapitiBob]

You switched from Winchester casings to Nosler.
More than likely the Noslers are thicker, meaning there is less room inside, hence raising pressures.

You were running near/at the high end of your charge to begin with if you were getting loose primer pockets after the 3rd reload.

Cases ARE a component!!
New workup for different components.

this

on both accounts

 

[rideold]

Thanks. Couple of clarifications.

- Prior to this we were shooting both the Hornady and Winchester brass with no over pressure.
- The batch of powder was the same.
- Ambient temperature was higher when we had no problems.
- This was the third reloading and over pressure started with the Winchester brass and continued with the hornady

Either way I'm starting over with a new load development. I'm still wanting to understand why things changed from one reloading to the next.

Should I be suspect of my mechanical scale? It is a RCBS.

 

[MThuntr]

Get some check weights but I doubt it's the scale. Don't mix brass because that's the likely issue. 43.5gr is 0.5gr off max for Hodgdon and 0.2gr off max from Barnes. I'd say you're already hot load based on loose primer pockets with 3 firings add the brass change and you could be dangerous hot. Start over.

 

[EastTNHunter]

If this was third firing then your primer pockets may have been “loosened” by previous high pressure loads, but just now exhibited themselves on this firing as the “straw that broke the camel’s back.”

Don’t mix brass. Check your trim length. Check your seating depth. All of these things can lead to pressure issues in addition to what has already been mentioned.

 

[BuckRut]

I would also say that the change in cases is the culprit. Especially without annealing that 3rd fired case is not the same as it was when it was a once or twice fired case.

 

[std7mag]

I would also say that the change in cases is the culprit. Especially without annealing that 3rd fired case is not the same as it was when it was a once or twice fired case.

Annealing, or lack thereof, would be my least pick of the possible culprits.
I've done 30 reloads on a test batch of 7mm-08AI with no I'll effect.

I'd go with hot load to begin with, and a change of components.
Add in possible trim length.

 

[Wind Gypsy]

Thanks. Couple of clarifications.

- Prior to this we were shooting both the Hornady and Winchester brass with no over pressure.
- The batch of powder was the same.
- Ambient temperature was higher when we had no problems.
- This was the third reloading and over pressure started with the Winchester brass and continued with the hornady

Either way I'm starting over with a new load development. I'm still wanting to understand why things changed from one reloading to the next.

Should I be suspect of my mechanical scale? It is a RCBS.

Your original post said nosler brass but now you’re saying winchester and hornady?

 

[Sheltowee]

Consistency got me there. I log all of my loads, case preparations. It’s easier to make changes then because everything else is static; only one variable changed or added to the load.
If you already do all of that too then try adding light crimp. It worked for me! You could either remove seating stem once seated and screw down the die 1/2 turn or leave all that alone, add Lee Factory Crimp die at the end of your process.
6.5 Staball is close to yet slower than H100V (think both are St. Mark’s creations). It’s very temp tolerant and low pressure. Barnes puts max load at 44g, Hodgdon max is 44.8g with both advising 2.75” OAL.
How about load up 43g, 44g, 45g keeping all else within recommended trim, seating, yadda yadda and add the same light crimp to all these test loads?

I'm pretty meticulous with my reloading process. Started with new Nosler brass, chamfered/deburred each case mouth, CCI BR-2 primers, started at 40.5 grains and worked up 2% each load to a max of 44.0. Best five shot group I could wring out was .928 inches but most were in the 1.4-1.75inch range. Disappointing from a consistently sub half-MOA rifle with Hornady SSTs, Nosler BTs, Hornady ELD-Ms and Sierra MatchKings. I worked up some MOA-ish loads with the LRX on top of H4350 after ladder testing and seating depth tests, but I'm still not enamored. May have to play around with crimping as you suggest in the offseason.

 

[BuckRut]

Annealing, or lack thereof, would be my least pick of the possible culprits.
I've done 30 reloads on a test batch of 7mm-08AI with no I'll effect.

I'd go with hot load to begin with, and a change of components.
Add in possible trim length.

I would agree. I didn't mean to imply that annealing would have solved the problem. Just emphasizing that the material properties of the case change with each firing and that although it is the same physical case it's not the same as it was before the last firing. Like you mentioned I think the load is on the hot end and just because the case was capable of taking the load without showing over-pressure signs on one firing doesn't mean it will with the next.

 

[Benfromalbuquerque]

I'm pretty meticulous with my reloading process. Started with new Nosler brass, chamfered/deburred each case mouth, CCI BR-2 primers, started at 40.5 grains and worked up 2% each load to a max of 44.0. Best five shot group I could wring out was .928 inches but most were in the 1.4-1.75inch range. Disappointing from a consistently sub half-MOA rifle with Hornady SSTs, Nosler BTs, Hornady ELD-Ms and Sierra MatchKings. I worked up some MOA-ish loads with the LRX on top of H4350 after ladder testing and seating depth tests, but I'm still not enamored. May have to play around with crimping as you suggest in the offseason.

That’s good news that H4350 produced so you know you’re in a good burn rate range. Let’s go super nerd on this. Like some have said on this thread, you could try annealing. Maybe add turning to the deburr/chamfer step. I’ve added a Limbsaver barrel x-ring and that has reduced barrel whip. Looks stupid, but you know, this ain’t style over function.

 

[rideold]

Your original post said nosler brass but now you’re saying winchester and hornady?

Ack. My mistake. It is Winchester and Hornady. Don't know where I pulled Nosler out of. That's what I get for off the cuff typing!

 

[rideold]

I would agree. I didn't mean to imply that annealing would have solved the problem. Just emphasizing that the material properties of the case change with each firing and that although it is the same physical case it's not the same as it was before the last firing. Like you mentioned I think the load is on the hot end and just because the case was capable of taking the load without showing over-pressure signs on one firing doesn't mean it will with the next.

That makes a ton of sense. Once fired is not the same as twice or thrice fired brass. I hadn't thought of that.